"Traditional implies age, unknown author, change..."

I'd disagree there - traditional can equally imply something that is composed today in a living tradition, and I'd say, by someone who is living in that tradition.

Extended narrative songs occur in all sorts of traditions around the world, some of which are very much alive. Whether the term ballad is used to include all these, or whether it should be more especially applied to the ballads from the tradition catalogued by Child, is a matter of choice.

Does the Oddyssey count as a ballad?